Merge pull request #66 from elekto-io/migration

Security updates and migration code for 0.6

.env.example

@@ -6,6 +6,7 @@ APP_URL=http://localhost
 APP_PORT=5000
 APP_HOST=localhost
 APP_CONNECT=http
+MIN_PASSCODE_LENGTH=
 
 DB_CONNECTION=mysql
 DB_HOST=localhost
@@ -24,3 +25,5 @@ META_SECRET=
 GITHUB_REDIRECT=/oauth/github/callback
 GITHUB_CLIENT_ID=
 GITHUB_CLIENT_SECRET=
+
+

config.py

@@ -104,3 +104,5 @@
     'redirect': env('GITHUB_REDIRECT', '/oauth/github/callback'),
     'scope': 'user:login,name',
 }
+
+PASSCODE_LENGTH = env('MIN_PASSCODE_LENGTH', 6)

elekto/controllers/elections.py

@@ -29,7 +29,7 @@
 from elekto.models import meta
 from elekto.core.election import Election as CoreElection
 from elekto.models.sql import Election, Ballot, Voter, Request
-from elekto.middlewares.auth import auth_guard
+from elekto.middlewares.auth import auth_guard, len_guard
 from elekto.core.encryption import encrypt, decrypt
 from elekto.middlewares.election import *  # noqa
 
@@ -92,6 +92,7 @@ def elections_candidate(eid, cid):
 @APP.route("/app/elections/<eid>/vote", methods=["GET", "POST"])
 @auth_guard
 @voter_guard
+@len_guard
 def elections_voting_page(eid):
     election = meta.Election(eid)
     candidates = election.candidates()
@@ -136,9 +137,37 @@ def elections_voting_page(eid):
         election=election.get(),
         candidates=candidates,
         voters=voters,
+        min_passcode_len=APP.config.get('PASSCODE_LENGTH')
     )
 
 
+@APP.route("/app/elections/<eid>/vote/view", methods=["POST"])
+@auth_guard
+@voter_guard
+@has_voted_condition
+def elections_view(eid):
+    election = meta.Election(eid)
+    voters = election.voters()
+    e = SESSION.query(Election).filter_by(key=eid).first()
+    voter = SESSION.query(Voter).filter_by(user_id=F.g.user.id).first()
+
+    passcode = F.request.form["password"]
+
+    try:
+        # decrypt ballot_id if passcode is correct
+        ballot_voter = decrypt(voter.salt, passcode, voter.ballot_id)
+        ballots = SESSION.query(Ballot).filter_by(voter=ballot_voter)
+        return F.render_template("views/elections/view_ballots.html", election=election.get(), voters=voters, voted=[v.user_id for v in e.voters], ballots=ballots)
+
+    # if passcode is wrong
+    except Exception:
+        F.flash(
+            "Incorrect password, the password must match with the one used\
+                before"
+        )
+        return F.redirect(F.url_for("elections_single", eid=eid))
+
+
 @APP.route("/app/elections/<eid>/vote/edit", methods=["POST"])
 @auth_guard
 @voter_guard

elekto/middlewares/auth.py

@@ -17,7 +17,7 @@
 import flask as F
 import base64
 from functools import wraps
-from elekto import constants
+from elekto import APP, constants
 
 
 def authenticated():
@@ -53,3 +53,18 @@ def decorated_function(*args, **kwargs):
 
         return f(*args, **kwargs)
     return decorated_function
+
+
+def len_guard(f):
+    @wraps(f)
+    def decorated_function(*args, **kwargs):
+        if F.request.method == "POST":
+            passcode = F.request.form["password"]
+            min_passcode_len = int(APP.config.get('PASSCODE_LENGTH'))
+            if 0 < len(passcode) < min_passcode_len:
+                F.flash(f"Please enter a passphrase with minimum {min_passcode_len} characters")
+                return F.redirect(F.request.url)
+        return f(*args, **kwargs)
+    return decorated_function
+
+

elekto/models/sql.py

@@ -11,19 +11,26 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
 #
 # Author(s):         Manish Sahani <rec.manish.sahani@gmail.com>
-
 import uuid
 import sqlalchemy as S
 
 from sqlalchemy.orm import sessionmaker, scoped_session
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.types import TypeDecorator, CHAR
+from sqlalchemy import event
 
 
 BASE = declarative_base()
 
+"""
+schema version, remember to update this
+whenever you make changes to the schema
+"""
+schema_version = 2
+
 
 def create_session(url):
     """
@@ -46,6 +53,7 @@ def create_session(url):
 def migrate(url):
     """
     Create the tables in the database using the url
+    Check if we need to upgrade the schema, and do that as well
 
     Args:
         url (string): the URL used to connect the application to the
@@ -54,12 +62,74 @@ def migrate(url):
             ie: <engine>://<user>:<password>@<host>/<dbname>
     """
     engine = S.create_engine(url)
+    update_schema(engine, schema_version)
     BASE.metadata.create_all(bind=engine)
+
 
     session = scoped_session(
         sessionmaker(bind=engine, autocommit=False, autoflush=False)
     )
     return session
+
+
+def update_schema(engine, schema_version):
+    """
+    Primitive database schema upgrade facility, designed to work
+    with production Elekto databases
+    
+    Currently only works with PostgreSQL due to requiring transaction
+    support for DDL statements.  MySQL, SQLite backends will error.
+    
+    Start by figuring out our schema version, and then upgrade 
+    stepwise until we match
+    """
+    db_version = 1
+    db_schema = S.inspect(engine)
+
+    if db_schema.has_table("election"):
+        if db_schema.has_table("schema_version"):
+            db_version = engine.execute('select version from schema_version').scalar()
+            if db_version is None:
+                """ intialize the table, if necessary """
+                engine.execute('insert into schema_version ( version ) values ( 2 )')
+    else:
+        """ new, empty db """
+        return schema_version
+
+    while db_version < schema_version:    
+        if engine.dialect.name != "postgresql":
+            raise RuntimeError('Upgrading the schema is required, but the database is not PostgreSQL.  You will need to upgrade manually.')
+
+        if db_version < 2:
+            db_version = update_schema_2(engine)
+            continue
+
+    return db_version;
+
+
+def update_schema_2(engine):
+    """
+    update from schema version 1 to schema version 2
+    as a set of raw SQL statements
+    currently only works for PostgreSQL
+    written this way because SQLalchemy can't handle the
+    steps involved without data loss
+    """
+    session = scoped_session(sessionmaker(bind=engine))
+
+    session.execute('CREATE TABLE schema_version ( version INT PRIMARY KEY);')
+    session.execute('INSERT INTO schema_version VALUES ( 2 );')
+    session.execute('ALTER TABLE voter ADD COLUMN salt BYTEA, ADD COLUMN ballot_id BYTEA;')
+    session.execute('CREATE INDEX voter_election_id ON voter(election_id);')
+    session.execute('ALTER TABLE ballot DROP COLUMN created_at, DROP COLUMN updated_at;')
+    session.execute('ALTER TABLE ballot DROP CONSTRAINT ballot_pkey;')
+    session.execute("ALTER TABLE ballot ALTER COLUMN id TYPE CHAR(32) USING to_char(id , 'FM00000000000000000000000000000000');")
+    session.execute('ALTER TABLE ballot ALTER COLUMN id DROP DEFAULT;')
+    session.execute('ALTER TABLE ballot ADD CONSTRAINT ballot_pkey PRIMARY KEY ( id );')
+    session.execute('CREATE INDEX ballot_election_id ON ballot(election_id);')
+    session.commit()
+
+    return 2
 
 
 class UUID(TypeDecorator):
@@ -94,6 +164,19 @@ def process_result_value(self, value, dialect):
             return value
 
 
+class Version(BASE):
+    """
+    Stores Elekto schema version in the database for ad-hoc upgrades
+    """
+    __tablename__ = "schema_version"
+
+    # Attributes
+    version = S.Column(S.Integer, default=schema_version, primary_key=True)
+
+@event.listens_for(Version.__table__, 'after_create')
+def create_version(target, connection, **kwargs):
+    connection.execute(f"INSERT INTO schema_version ( version ) VALUES ( {schema_version} )")
+
 class User(BASE):
     """
     User Schema - registered from the oauth external application - github
@@ -185,11 +268,11 @@ class Voter(BASE):
 
     id = S.Column(S.Integer, primary_key=True)
     user_id = S.Column(S.Integer, S.ForeignKey("user.id", ondelete="CASCADE"))
-    election_id = S.Column(S.Integer, S.ForeignKey("election.id", ondelete="CASCADE"))
+    election_id = S.Column(S.Integer, S.ForeignKey("election.id", ondelete="CASCADE"), index=True)
     created_at = S.Column(S.DateTime, default=S.func.now())
     updated_at = S.Column(S.DateTime, default=S.func.now())
-    salt = S.Column(S.LargeBinary, nullable=False)
-    ballot_id = S.Column(S.LargeBinary, nullable=False)  # encrypted
+    salt = S.Column(S.LargeBinary)
+    ballot_id = S.Column(S.LargeBinary)  # encrypted
 
     # Relationships
 
@@ -227,7 +310,7 @@ class Ballot(BASE):
 
     # Attributes
     id = S.Column(UUID(), primary_key=True, default=uuid.uuid4)
-    election_id = S.Column(S.Integer, S.ForeignKey("election.id", ondelete="CASCADE"))
+    election_id = S.Column(S.Integer, S.ForeignKey("election.id", ondelete="CASCADE"), index=True)
     rank = S.Column(S.Integer, default=100000000)
     candidate = S.Column(S.String(255), nullable=False)
     voter = S.Column(S.String(255), nullable=False)  # uuid

elekto/templates/views/elections/single.html

@@ -83,12 +83,12 @@ <h2 class="title pb-0 mb-0">
                 </div>
                 {% else %}
                 <div class="col-md-6">
-                    <form action="{{ url_for('elections_edit', eid=election['key']) }}" method="post">
+                    <form action="{{ url_for('elections_view', eid=election['key']) }}" method="post">
                         <input type="hidden" name="csrf_token" value="{{ csrf_token() }}"/>
                         <div class="input-group">
                             <input type="password" name="password" class="form-control" placeholder="Enter the passphrase" id="">
                             <div class="input-group-append">
-                                <button type="submit" class="btn btn-dark">Revoke Ballot</button>
+                                <button type="submit" class="btn btn-dark">View Ballot</button>
                             </div>
                         </div>
                     </form>

elekto/templates/views/elections/view_ballots.html

@@ -0,0 +1,116 @@
+{% extends 'layouts/app.html' %}
+
+{% block header %}
+<h1>{% block title %}{{ election['name'] }}{% endblock %}</h1>
+{% endblock %}
+
+{% block breadcrums %}
+<a href="{{ url_for('elections') }}" class="breadcrums">elections</a>
+<a href="{{ url_for('elections_single', eid=election['key']) }}" class="breadcrums breadcrums-active">{{
+    election['name'] }}</a>
+{% endblock %}
+
+{% block content %}
+
+
+<div class="">
+    <div class="space--md pb-0">
+        <h1 class="banner-title space-lr">
+            {{ election['name'] }}
+        </h1>
+        <p class="banner-subtitle space-lr mb-2rem">
+            <span class="mr-5px">{{ election['organization'] }}</span>
+            <span class="text-muted mr-5px">|</span>
+            <small class="badge mr-5px badge-{{  election['status'] }} ">{{ election['status'] }}</small>
+            <span class="text-muted mr-5px">|</span>
+            {% if g.user.username in voters['eligible_voters'] %}
+            <small class="badge badge-blue ">eligible</small>
+            {% else %}
+            <small class="badge badge-blue">Not eligible</small>
+            {% endif %}
+        </p>
+        <div class="description space-lr pb-0">
+            {{ election['description'] | safe }}
+        </div>
+    </div>
+    <div class="space--md pt-0">
+        <h4 class="title space-lr mb-1rem">
+            Your Ballot
+        </h4>
+        <div class="space-lr"> 
+            {% for ballot in ballots %}
+            <div class="boxed-hover row" style="border: 1px solid #80808012;">
+                <div class="col-10 pt-5px pl-0">
+                    <h6 class="title mt-5px pb-0 mb-0">
+                        {{ ballot.candidate }}
+                    </h6>
+                </div>
+                <div class="col-2 text--right">
+                    <h6 class="title mt-5px pb-0 mb-0">
+                        {{ ballot.rank }}
+                    </h6>
+                </div>
+            </div>
+            {% endfor %}
+        </div>
+        <p class="disclaimer space-lr mt-1rem">
+          {% if election['status'] == 'running' and g.user.username in voters['eligible_voters'] %}
+              {% if g.user.id in voted %}
+                  You have cast your vote.
+              {% else %}
+                  You have not yet voted in this election.
+              {% endif %}
+          {% endif %}
+            Voting starts at <b>{{ election['start_datetime'] }} UTC</b> and ends at
+            <b>{{ election['end_datetime'] }} UTC</b>.
+            {% if g.user.username not in voters['eligible_voters'] %}
+                If you wish to participate in the election, please fill the
+                <a href="{{ url_for('elections_exception', eid=election['key']) }}"><b>exception form</b></a>
+                before <b>{{ election['exception_due'] }}</b>.
+            {% endif %}
+        </p>
+    </div>
+
+    <div class="space--md pt-0">
+        <div class="space-lr row">
+            {% if election['status'] == 'running' and g.user.username in voters['eligible_voters'] %}
+                {% if g.user.id not in voted %}
+                <div class="col-md-2 pr-0">
+                    <a href="{{ url_for('elections_voting_page', eid=election['key'])}}" class="btn btn-dark pl-3rem pr-3rem">Vote</a>
+                </div>
+                {% else %}
+                <div class="col-md-6">
+                    <form action="{{ url_for('elections_edit', eid=election['key']) }}" method="post">
+                        <input type="hidden" name="csrf_token" value="{{ csrf_token() }}"/>
+                        <div class="input-group">
+                            <input type="password" name="password" class="form-control" placeholder="Enter the passphrase" id="">
+                            <div class="input-group-append">
+                                <button type="submit" class="btn btn-dark">Revoke Ballot</button>
+                            </div>
+                        </div>
+                    </form>
+                </div>
+                {% endif %}
+            {% endif %}
+            <div class="col-md-6
+                {% if election['status'] == 'running' and g.user.username in voters['eligible_voters'] %}
+                pl-0
+                {% endif %}
+                ">
+                {% if election['status'] == 'completed' %}
+                    {% if election['results'] %}
+                    <a href="{{ url_for('elections_results', eid=election['key'])}}" class="btn btn-dark">Results</a>
+                    {% else %}
+                    <button class="btn btn-dark" disabled>Results (not published)</button>
+                    {% endif %}
+                {% endif %}
+
+                {% if g.user.username in election['election_officers'] %}
+                <a href="{{ url_for('elections_admin', eid=election['key'])}}" class="btn btn-dark">Admin</a>
+                {% endif %}
+            </div>
+        </div>
+    </div>
+</div>
+
+{% endblock %}

elekto/templates/views/elections/vote.html

@@ -61,7 +61,7 @@ <h6 class="title mt-5px pb-0 mb-0">
                 <div class="mt-2rem pt-2rem row">
                     <div class="col-md-6 text-justify">
                         <small>
-                            If you wish to be able to revoke this ballot, please enter a passphrase here. If you do not enter a passphrase, you will not be able to change or delete your vote later.
+                            If you wish to be able to revoke this ballot, please enter a passphrase of minimum {{ min_passcode_len }} characters here. If you do not enter a passphrase, you will not be able to change or delete your vote later.
                         </small>
                     </div>
                     <div class="col-md-6 pt-5px">